truncate - Man Page

• Set a size of 10 GB to an existing file, or create a new file with the specified size: truncate --size 10G filename
• Extend the file size by 50 MiB, fill with holes (which reads as zero bytes): truncate --size +50M filename
• Shrink the file by 2 GiB, by removing data from the end of file: truncate --size -2G filename
• Empty the file's content: truncate --size 0 filename
• Empty the file's content, but do not create the file if it does not exist: truncate --no-create --size 0 filename

tldr.sh

truncate OPTION... FILE...

Shrink or extend the size of each FILE to the specified size

A FILE argument that does not exist is created.

If a FILE is larger than the specified size, the extra data is lost. If a FILE is shorter, it is extended and the sparse extended part (hole) reads as zero bytes.

Mandatory arguments to long options are mandatory for short options too.

-c,  --no-create

do not create any files

-o,  --io-blocks

treat SIZE as number of IO blocks instead of bytes

-r,  --reference=RFILE

base size on RFILE

-s,  --size=SIZE

set or adjust the file size by SIZE bytes

--help

display this help and exit

--version

output version information and exit

The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units are K,M,G,T,P,E,Z,Y,R,Q (powers of 1024) or KB,MB,... (powers of 1000). Binary prefixes can be used, too: KiB=K, MiB=M, and so on.

SIZE may also be prefixed by one of the following modifying characters: '+' extend by, '-' reduce by, '<' at most, '>' at least, '/' round down to multiple of, '%' round up to multiple of.

Written by Padraig Brady.

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
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Copyright © 2024 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

dd(1), truncate(2), ftruncate(2)

Full documentation <https://www.gnu.org/software/coreutils/truncate>
or available locally via: info '(coreutils) truncate invocation'

fallocate(1), swapon(8), truncate(2), virt-resize(1), virt-sparsify(1).